Blood in Breast Milk

Occasionally you may notice that your breast milk is streaked with red (or pink or brown) after you have expressed your milk or after your baby has spit up some breast milk after a feed. Naturally you will be worried that it might be blood and where it might have come from. Has it come from a cracked nipple or deeper in your breast, could it be from your baby? If it is from your breast will it harm your baby? This article looks at common causes of blood in breast milk and answers frequently asked questions.

Signs of blood in breast milk

A little blood in breast milk in the early days of breastfeeding is quite common due to the changes within the breast1. Small amounts of blood will often go unnoticed unless a mother is expressing her milk or her baby spits up blood stained milk. Blood in breast milk may colour breast milk bright red, pink, black, olive green or a chocolate brown colour 2. However, bear in mind that breast milk and colostrum come in a variety of different colours including blue, green, brownish, yellow, gold and clear3. If substantial amounts of blood are swallowed there may be black flecks of blood in the baby’s poop or the poop may even be black and tarry. If the bleeding continues past these first few days, the mother should check with her doctor.

Common causes of blood in breast milk

Common causes of blood in breast milk include:

  • “Rusty pipe syndrome” when ducts and milk making cells grow and stretch after birth
  • A cracked or damaged nipple that bleeds as baby sucks
  • Damaged capillaries in the breast due to engorgement or rough handling
  • Intraductal pailloma; a small benign growth on the milk duct lining which bleeds
  • Fibrocystic changes (lumpy breasts)

Although not usually serious, it’s always a good idea to mention any blood to your health care provider. Rarely, a bloody nipple discharge can be an indication of breast cancer4. Your health professional will also be able to help determine whether the blood could be from the baby instead of your milk in the case of blood stained regurgitated milk.

Rusty pipe syndrome

This is the name given to small amounts of blood seen in breast milk during the first week or so after birth. It’s thought to be due to extra blood flow to the breast and fast development of glandular tissue. It is discussed in Dr Jack Newman’s Guide to Breastfeeding:

It is not surprising that sometimes blood vessels leak a little blood into a duct, and it then comes out of the nipple. It is not dangerous for the mother or the baby. Sometimes when a baby swallows blood he may spit it up because it irritates his stomach, but it really does him no harm. The bleeding usually disappears by 7 to 10 days after birth. Breastfeeding must not be interrupted.

If bleeding carries on after baby is a week old or if bleeding happens at a later stage than the first week, continue breastfeeding but always check with your doctor (Newman, 2014).

Cracked or damaged nipples

If the cause of blood in breast milk is due to a mother’s cracked or damaged nipples, it is important to find the cause of the damage so the nipples can heal. See our article on causes of sore nipples or contact your IBCLC lactation consultant for help with positioning and latching your newborn baby.

Damaged capillaries

Breast damage from rough handling such as pressing too hard during hand expression or using a pump with a very high vacuum could cause bleeding from broken capillaries (tiny blood vessels) as they are very delicate.

Intraductal pailloma

An intraductal papilloma is a small growth in the lining of a duct near the nipple. It is usually noncancerous and doesn’t cause pain5 but can bleed into the duct when disturbed by breastfeeding or pumping and it is a common reason for blood in breast milk 6. Walker explains that if the baby tolerates the blood they can continue breastfeeding but if the baby keeps spitting up, because the blood is making them sick, the mother may have to pump the affected breast until it is clear of blood which usually takes 3-7 days.

Fibrocystic changes

Fibrocystic breasts is the name used for a group of symptoms in the glandular breast tissue including breast pain, solid lumps and cysts. Breastfeeding A Guide for the Health Profession discusses that fibrocystic breasts are a cause of a discharge of blood from the nipple in pregnancy and lactation in approximately a third of cases but it is not a contraindication to breastfeeding. The authors mention one case where fibrocystic breasts were found to be the cause of an infant vomiting due to the volume of blood in breast milk.

Frequently asked questions

Can I feed my baby breast milk that has blood in it?

Jack Newman, Canadian paediatrician and breastfeeding expert says that although blood will cause a baby to spit up more, breastfeeding can continue. He explains:

Taking the baby off the breast is often suggested if the mother’s nipples bleed from a crack or abrasion. But blood in the milk is not a reason to take the baby off the breast. The issue is the pain the mother feels, not the blood. Blood in the baby’s stomach can cause spitting up but is not dangerous. If we can make the mother’s pain tolerable, even if the nipples continue to bleed, let’s keep the baby on the breast. If the damage is minimized by fixing the way the baby takes the breast, the abrasions/cracks will heal and the bleeding will stop.

Breastfeeding author and lactation consultant Nancy Mohrbacher Breastfeeding Answers Made Simple, 2010, p 702 agrees that it is OK to continue breastfeeding and that the bleeding will not be harmful to the baby.

What if there is a lot of blood?

If your baby has drunk a lot of blood stained breast milk they might have very dark coloured poop or may spit up very blood-stained milk. The blood can form a large clump in the stomach and this might look like a lot of blood when spit up—always check with your health professional for immediate medical advice 7.

Could the blood be from my baby?

Your health professionals will be able to determine whether the blood is from baby or the breast by checking the regurgitated blood for foetal or adult haemoglobin 8.

Other causes of pink breast milk

Food pigments may colour breast milk

Sometimes a food in mother’s diet may colour her breast milk pink e.g. beetroot. In Baby Poop: What Your Pediatrician May Not Tell You, author Linda Palmer says that the pigments from natural foods such as beets are usually good antioxidants and don’t need to be avoided. She adds that if if the pigment has coloured the milk this means it has passed through mother’s system undigested and will probably go through baby’s system the same way.

Bacteria can colour milk pink

Thomas Hale describes another possible cause of pink/red milk that may not be blood; a bacteria called Serratia marsescens. Although S. marsescens is normally harmless and commonly found in children’s gastrointestinal tracts it can be the cause of infection, especially for premature babies.

It is unlikely that a baby feeding directly from the mother’s breast will consume enough bacteria to cause disease. However improper handling of breast milk may allow the bacteria to multiply to numbers capable of producing disease. Refrigeration of breast milk and breastfeeding equipment is usually sufficient to prevent Serratia from multiplying and generating pigment.

The author advises never feeding a baby pink-red discoloured breast milk until cleared by a doctor. See the full article for further information.

Expressed breast milk and pump


A little blood in breast milk is not harmful to your breastfed baby and is a common occurrence in the first week or so after a baby’s birth. Reasons for short periods of blood in breast milk include rusty pipe syndrome, cracked bleeding nipples, broken capillaries in the breast or an intraductal papilloma. Any blood in breast milk that continues past the first week after birth, or blood in breast milk that arrives later during lactation should be discussed with your doctor but in most cases breastfeeding can continue.